System and Method for Heart and Activity Monitoring

ABSTRACT

A system and method determining physiological status of a patient. A determination is made whether the patient is sleeping. The amplitude and change in voltage over time of any intramyocardial electrogram is measured for a right ventricle and a left ventricle of a heart of the patient for a predefined number of heartbeats at a specified time interval in response to determining the patient is asleep. The measurements are averaged for the right ventricle and left ventricle. The averaged measurements are transmitted to a receiver for communication to an intended recipient.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/712,284, filed Feb. 27, 2007, which in turn claims priority to U.S.Provisional Application No. 60/776,834, filed Feb. 27, 2006, each ofwhich is hereby incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

Thousands of people die each year because of heart related problems,including heart disease, heart attack (myocardial infarction), stroke,and heart failure. In many cases, significant heart problems may becorrected through medication, transplant, stenting, valve replacement,medical consultation, or other forms of medical intervention. Medicalpersonnel need an effective method of monitoring the patient's heart fordifferent symptoms, conditions, and parameters in order to provideeffective treatment.

For the most part, heart monitoring requires that the patient visit thephysician for an electrocardiogram (ECG) and/or other diagnostic tests.Frequently, the ECG by itself is only one of the many diagnostic toolsthat the physician has in his/her armamentarium, and not adequate aloneto diagnose transplant rejection, heart failure, and other heart relateddisorders.

Current heart monitoring systems provide limited heart monitoringcapabilities. Other systems are ineffective at detecting problemsbecause of patient movement, respiration, inspiration, and emotional orphysiologic stress. Frequently, traditional methods of heart monitoringare ineffective or incapable of detecting the subtle heart performancemetrics that may indicate that heart failure or transplant rejection ispresent or imminent.

When cardiac events occur infrequently (paroxysmal occurrences), ECG maynot be effective in detecting certain heart events, such as arrhythmias,tachycardia (faster than normal heart rate), bradycardia (slower thannormal heart rate), premature ventricular contractions (PVC), bigeminy,trigeminy, or other abnormal rhythms.

In many dire situations, a heart transplant is the only option for thepatient. For these patients, who are placed on anti-rejectionmedications, anti-inflammatory medication, and any host of othermedications, assessment of transplant rejection is of paramountimportance. In order to assess rejection, patients require frequentendomyocardial biopsies (EMB).

An EMB is the process of removing tissue from living patients formicroscopic diagnostic examination. An EMB requires that small pieces ofheart tissue be removed and examined under a microscope. To get thesample of heart tissue, a doctor places a small catheter or tube into alarge vein in the neck or a large artery in the groin, which is thenpassed into the heart. Tiny pieces of the heart tissue are removed andsent to the lab where they are microscopically examined. Biopsies mayalso be performed if the doctor suspects a heart related disease notrelated to transplant, or if the heart is not pumping well for unknownreasons.

Biopsies are invasive, painful and frequently leave large scars. In mostcases, heart patients dread the thought of a biopsy which adds topost-operative stress and surgical dissatisfaction. The EMB routine fortransplant patients varies from 13 to 22 EMBs in the first yearfollowing transplant. This form of transplant monitoring for rejectionis the standard of care today, and may be difficult, time consuming,expensive, and painful. A small percentage of yearly EMBs result inpatient death. As a result, heart monitoring is still plagued by manydifficulties and complications despite the many improved techniques andtechnologies available in modern medicine.

SUMMARY OF THE INVENTION

To provide additional health monitoring of a patient, a system andmethod of determining physiological status of a patient is disclosed. Adetermination is made whether the patient is sleeping. The amplitude andchange in voltage over time of any intramyocardial electrogram ismeasured for a right ventricle and a left ventricle of a heart of thepatient for a predefined number of heartbeats at a specified timeinterval in response to determining the patient is asleep. Themeasurements are averaged for the right ventricle and left ventricle.The averaged measurements are transmitted to a receiver forcommunication to an intended recipient.

Another embodiment includes a method for determining activity levels ofa patient. An activity level is determined based on activity of thepatient. The activity is measured by piezoelectric accelerometers in asurgically implanted monitor. Data is measured and stored regarding timeawake and moving, activity amplitude, activity duration, andtemperature. The data is transmitted to a receiver.

Yet another embodiment includes a heart monitor. The monitor includesone or more electrodes for sensing electrical cardiac signals from aheart at different locations in the heart. The electrodes includepiezoelectric accelerometers for measuring motion of the differentlocations. One or more amplifiers operatively interconnected to theelectrodes are configured to filter the electrical signals received fromthe electrodes. A monitor piezoelectric accelerometer is configured tomeasure activity levels of a patient. A processor operatively connectedto the amplifiers is configured to control the electrical signals sensedby the electrodes. A storage device is operatively connected to theprocessor and is configured to store data associated with the electricalsignals and activity levels. Telemetry circuitry operatively connectedto the processor is configured to wirelessly send the data to areceiver.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative embodiments of the present invention are described indetail below with reference to the attached drawing figures, which areincorporated by reference herein and wherein:

FIG. 1 is a perspective diagram of a health monitoring system inaccordance with the illustrative embodiments of the present invention;

FIGS. 2A-C represent heart wave forms in accordance with theillustrative embodiments of the present invention;

FIG. 3 is a graph illustrating heart rejection in accordance with theillustrative embodiments of the present invention;

FIG. 4 is a block diagram of a monitor system in accordance with theillustrative embodiments of the present invention;

FIG. 5 is an alternative embodiment of a monitor system in accordancewith the illustrative embodiments of the present invention;

FIG. 6 is an embodiment of an external monitor system in accordance withthe illustrative embodiments of the present invention;

FIG. 7 is an example of a screw-in myocardial electrode lead inaccordance with the illustrative embodiments of the present invention;

FIG. 8 is a sample of heart data in accordance with the illustrativeembodiments of the present invention;

FIG. 9 is an illustrative graph of physical activity in accordance withthe illustrative embodiments of the present invention;

FIG. 10 is an example of data recorded by a monitor in accordance withthe illustrative embodiments of the present invention;

FIG. 11 is an example of data recorded by a monitor in accordance withthe illustrative embodiments of the present invention;

FIG. 12 is an example of data recorded by a monitor in accordance withthe illustrative embodiments of the present invention;

FIG. 13 is a graphical illustration of threshold levels in accordancewith the illustrative embodiments of the present invention;

FIG. 14 is a graphical illustration of adjusted threshold levels inaccordance with the illustrative embodiments of the present invention;

FIG. 15 is a flowchart for a process for inserting a heart monitoringdevice in accordance with the illustrative embodiments of the presentinvention;

FIG. 16 is a flowchart of a process for performing heart monitoringduring sleep in accordance with the illustrative embodiments of thepresent invention;

FIG. 17 is a flowchart of a process for measuring activity levels inaccordance with the illustrative embodiments of the present invention;

FIG. 18 is a flowchart of a process for detecting heart events inaccordance with the illustrative embodiments of the present invention;

FIG. 19 is an example page for demographics in a graphical userinterface in accordance with the illustrative embodiments of the presentinvention;

FIG. 20 is an example page for patient listing in a graphical userinterface in accordance with the illustrative embodiments of the presentinvention;

FIG. 21 is an example page for a new patient enrollment in a graphicaluser interface in accordance with the illustrative embodiments of thepresent invention;

FIG. 22 is an example page for setting parameters in a graphical userinterface in accordance with illustrative embodiments of the presentinvention; and

FIG. 23 is an example page for a recorded event in a graphical userinterface in accordance with illustrative embodiments of the presentinvention.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective diagram of a health monitoring system inaccordance with the illustrative embodiments of the present invention.The health monitoring system 100 of FIG. 1 includes various elementsincluding a home 101, a patient 102, a monitor 104, a mobile receiver106, a transceiver 108, a network 110, a clinic 112, a computer 114, anda printer 116.

The heart monitoring system 100 monitors the health of the patient 102.In particular, the heart monitoring system 100 may be used to monitorthe overall physiological status of the patient 102. This includes thestatus of the patient's heart. For example, the patient 102 may haverecently undergone a heart transplant surgery during which the monitor104 was surgically implanted. As a result, the health monitoring system100 is able to record heart data including potential symptoms ofrejection.

The monitor 104 is surgically implanted in the patient 102 to record,analyze and store vital health information. The monitor 104 may be aphysiologic status monitor without leads attached to the patient's heartor may include electrode leads attached to the patient's heart and isfurther described by FIGS. 4-8. The monitor 104 may function as anImplantable Rejection Assessment Monitor (IRAM) and/or anintramyocardial electrogram (IMEG) monitor. In one embodiment, themonitor 104 may record and store data when the patient 102 is sleeping,resting, or in bed at home 101. This allows the monitor 104 to take moreeffective measurements because the patient 102 is not experiencing someof the electrocardiographic variations associated with emotional orphysiological stress, and other stimulus of wakefulness that may affecteffective heart measurements.

Data recorded, analyzed and stored by the monitor 104 may be wirelesslysent to the mobile receiver 106 or the transceiver 108. The healthmonitor system may include the mobile receiver 106, the transceiver 108,or both based on the needs of the patient 102. The monitor 104 maytransmit the data using a low power radio frequency (RF) signal or otherdata signal for communicating the recorded data to the mobile receiver106 or the transceiver 108. For example, the data signal may be aBLUETOOTH® or WIFI® signal or low-power equivalents. The monitor 104,mobile receiver 106, or transceiver 108 may format the data recorded bythe monitor 104 for transmission or communication. For example, thetransceiver 108 may format the data into packets for transmission acrossan Internet Protocol (IP) network. In other embodiments, the format maybe any communication format suitable for transmitting and reassemblingthe data sent from the monitor. The monitor may transmit the data to themobile receiver 106 and transceiver 108 using numerous communicationschedules. In one embodiment, the monitor 104 transmits the data at aspecified time each morning around the time the patient 102 is waking upfrom a night's sleep. In another embodiment, the monitor 104 transmitsdata to the mobile receiver 106 and transceiver 108.

In different embodiments, the monitor 104 may communicateunidirectionally or bidirectionally with the mobile receiver andtransceiver 108. For example, the monitor 104 may receive a handshake orverification signal from the mobile receiver 106 or transceiver 108indicating that data was successfully received during a transmission orthat the data needs to be resent because an error, fault, or otherproblem occurred during transmission. Alternatively, the transceiver 108may communicate with the monitor 104 to send control signals, updatesoftware or logic, or send other parameters for operational oradministrative use by the monitor 104.

The mobile receiver 106 may be a battery powered wireless device forreceiving data from the monitor 104 and then retransmitting the data toa specified interface. The mobile receiver 106 may be worn by thepatient 102 or otherwise attached to the patient 102 or the patient'sclothing. The mobile receiver 106 may use general packet radio service(GPRS), a global system for mobile (GSM) communication data transmissiontechnique that transmits data in packets rather than using a continuouschannel. GPRS allows the mobile receiver 106 to make efficient use ofavailable radio spectrum.

In one embodiment, the mobile receiver 104 may transmit the data to thetransceiver 108. In another embodiment, the mobile receiver 104 maytransmit the data through a wireless interface to the network 110. Thenetwork 110 may communicate the data to the computer 114 for subsequentanalysis by a doctor, technician, or medical specialist. The data may bestored in a database internal to the computer 114 or externallyconnected. The wireless interface may be a network server, website, orother interface that receives the data before communicating it to thecomputer 114.

The transceiver 108 is a combination of hardware and software elementsthat receives data from the monitor 104. In one embodiment, thetransceiver communicates unidirectionally. In other embodiments, thetransceiver 108 may both send and receive data through the network 110.The transceiver 108 may incorporate communications hardware, such as alocal area network card, modem, or other similar telemetry componentsfor sending and receiving data through the network 110. The network 110may be a private, public, hardwired, wireless, or virtual network or anycombination thereof. The transceiver 108 may be connected to the networkwirelessly or through a wired connection, such as a dial-up, cable, DSL,or other connection. A wireless connection may be WIFI®, WIMAX,satellite, or other wireless or cellular technology. For example,transceiver 108 may be connected to a DSL line that communicates withthe computer 114 through the network 110, wherein the network 110 is theInternet.

The computer 114 may be a computing device equipped to receive data froma network. The computer 114 may be a desktop computer, laptop, personaldigital assistant (PDA), cellular phone, or other data processingsystem. The computer 114 may include software or hardware forreconstructing the data for display to a doctor or other user. Thecomputer 114 may include a graphical user interface or web browsingapplication for accessing the data from the monitor 104. In oneembodiment, the data from the monitor 104 may be stored in a web serverthat is part of the network 110. The computer 114 may use acommunications line to access, download, archive, or otherwise use thedata. For example, when the patient comes to the clinic 112 to visitwith the doctor, the doctor may use the computer 114 to show the patient102 heart and activity levels. Alternatively, the computer 114 may senddata to the interconnected or wireless printer 116 to view a hard copyof the data, data graphs, or other information.

FIGS. 2A-C represent heart wave forms in accordance with theillustrative embodiments of the present invention. FIGS. 2A-C may bemeasured by a heart monitor, such as monitor 104 of FIG. 1. FIGS. 2A-Cinclude waveforms 202, 204, and 206. The waveforms 202, 204 and 206 maybe measured by one or more electrode leads attached to the heart. Theelectrode lead may be attached to the right and left ventricles of theheart in various positions. For example, the electrode leads may bemechanically attached to the myocardial muscle of the heart or they maybe floating inside the ventricle of the heart. The waveforms 202, 204,and 206 represent the depolarization and repolarization of cells in theneuromuscular fibers that result in contractions of the heart. As aresult, the waveforms 202, 204, and 206 represent the electricalactivity of a cellular contraction and an action potential. Thisactivity occurs because of the interaction of sodium and potassiumwithin a membrane. Neuromuscular fibers both conduct electrical signalsand are muscular fibers that contract.

In FIG. 2A the P wave 208 represents atrial electrical activity whichcauses the atrium of the heart to contract. The depolarization of theventricle is the electrical signal that causes ventricular contractionas represented by the Q wave 210, R wave 212, and S wave 214. The T wave216 represents the electrical repolarization of the ventricles.

In FIG. 2B waveform 204 shows the leading edge of a cellular actionpotential including the resting level 218, threshold 220, rising phase222, peak 224, repolarizattion 226, and hyperpolarization 228. The risetime or derivative of the voltage (dV/dt) of this leading edge changeswhen a transplanted heart experiences the onset of rejection when theamplitude may or may not change. Because these signals are in a higherfrequency domain than that measured with a standard electrocardiographicrecorder, approximately 0.05 to 150 Hz, it is imperative to have a widerupper frequency spectrum. The monitor amplifier used to view this signalshould cover a frequency of 2-3 Hz at the low end to 250 to 300 Hz atthe upper end. The resting level 218 is the fully repolarized levelbefore any new contractions may occur. The threshold 220 is when theelectrochemical reaction of sodium and potassium reaches a point atwhich cellular contraction is initiated. The rising phase 222 isparticularly important because it is the measure of the change involtage over time recorded by the monitor. The rising phase 222 may alsobe referred to as the rise time or slope. The monitor is able to measurethe change in voltage during the rise time.

The rise time is the time that passes between the threshold 220 and thepeak 224. For example, if dV/dt is changing from 10 mv/lms to 10 mv/1.5ms, indicating a slower cellular signal propagation time, a hearttransplant patient may be experiencing signs of rejection. In anotherexample, when a patient's dV/dt decreases, the patient's heart may beshowing signs of an upcoming cardiac event.

Hyperpolarization 228 is the voltage level below that of the restingpotential. The measurement of hyperpolarization sometimes appears on asurface electrocardiogram as an elevation or depression of the voltagemeasured between the Q wave 210 and the T wave 216. Changes in thisvalue may indicate cardiac ischemia or poor myocardial oxygenation.

Most heart monitors only measure the peak 224 associated with theamplitude. Heart monitors are unable to measure the slope of thewaveform 204 with an ECG machine having a high end frequency ofapproximately 150 Hz because the frequency component of interest isabove 200 Hz. The amplitude may change based on electrode position whichmay vary as the patient breaths and the heart contracts. However, theslope and rise time is relatively constant even when the amplitudechanges.

In FIG. 2C waveform 206 represents multiple, repetitive waveformssimilar to the single waveform 204, but as measured by an IRAM with afrequency response of 2-3 Hz at the low end to 250-300 Hz at the upperend.

FIG. 3 is a graph illustrating heart rejection in accordance with theillustrative embodiments of the present invention. Graph 300 showsvarious elements including IMEG amplitude and dV/dt 302, rejection line304, timeline 306, heartbeat waveform 308, and points 310 and 312. Graph300 illustrates that even though the amplitude of the heartbeat waveform308 as measured by an intramyocardial electrogram remains relativelyconsistent as shown by the heartbeat waveform, the patient begins toexperience rejection at point 310. Therefore, measuring amplitude aloneis not as effective as measuring both amplitude and slope in order todetect rejection.

A monitor, such as monitor 104 of FIG. 1, may be used to measure thechange in voltage of the heartbeat waveform 308 over time or dV/dt. Asdescribed in FIGS. 2A-B, as the IMEG amplitude and dV/dt 302 begin todecrease, the dV/dt of the heartbeat waveform 308 begins to decreaseindicating that rejection or a significant cardiac event is likely tooccur. Even though amplitude of the heartbeat waveform 308 may notindicate rejection is likely, by measuring the change in voltagemeasured over time, a doctor may more effectively prescribe medicationsand take other actions to prevent rejection, illness, or death of thepatient. By detecting symptoms of rejection early the monitor allows thedoctor more flexibility in treating the patient and the doctor may notbe required to use extreme levels of steroids, antibiotics, and othercardioactive pharmaceuticals that may not be best for the patient'soverall well-being.

FIG. 4 is a block diagram of a monitor system in accordance with theillustrative embodiments of the present invention. The monitor system400 includes various elements including a receiver 402, a heart monitor404, electrode leads 406 and 408, and a heart 410. The receiver 402 is aparticular implementation of the portable receiver 106 or thetransceiver 110 of FIG. 1. The heart monitor 404 and electrode leads 406and 408 are particular implementations of the monitor 104 of FIG. 1. Theelements of the heart monitor 404 may be discrete components or may be asingle integrated circuit that may be programmed or otherwise configuredwith various hardware, software and firmware surgically implanted insitu.

The heart monitor 404 further includes a magnetic reed switch 412,telemetry circuitry 414, a thermistor 416, a memory 418, a processor420, analog to digital converters (A/D) and peak detector 422,amplifiers (amp) 426, 428, 430, 432, and 434, and piezoelectricaccelerometer 436. The electrode leads 406 and 408 further includepiezoelectric accelerometers 438 and 440. The heart monitor 404 may bean internal heart monitor (IHM), implantable rejection assessmentmonitor (IRAM), an implantable heart failure monitor (IHFM), animplantable transient event recorder (ITER), or an external transientevent recorder (ETER). In one embodiment, the electrode leads 406 and408 may be connected to the heart 410 using the electrode leads 406 and408. In other embodiments, external ECG electrodes are employed or theheart monitor 404 may not require electrodes to monitor the patient.Each embodiment may include one or more leads and the number of theamplifiers 426, 428, 430, and 432 may also vary based on whether thepiezoelectric accelerometers are integrated as part of the electrodeleads 406 and 408.

The receiver 402 may be an external telemetry device for wirelesslyreceiving data from the heart monitor 404. The receiver 402 may includea memory, logic, processor, and other circuitry and software forreceiving and processing data from the heart monitor 404. The receiver402 may also send data to the heart monitor 404, including a handshake,software, programming, and parameter updates as previously described. Inone embodiment, the receiver 402 may include a series of colored lightsor a screen for displaying text that may indicate whether data has beensent and received. The colored lights may also specify whether thepatient needs to call the doctor based on the received data. Forexample, if everything is received and transmitted correctly a greenlight may be displayed. If a red light is displayed, the receiver 402may indicate that the patient needs to call the doctor as soon aspossible.

In one embodiment, the receiver may include memory and logic fordetermining whether the received data indicates rejection, a heartevent, or other condition that warrants immediate action by the patientor the patient's doctor. For example, a text display may tell thepatient to “take an extra dose of antibiotics, aspirin, and call yourdoctor”.

The heart monitor 404 may be formed from a titanium enclosure. Titaniumproduces on its own, titanium oxide, which is body-compatible and isused in conventional cardiac pacemakers. The heart monitor 404 may alsobe plastic or a composite. All of the components within the heartmonitor 404 are body compatible and are secured in place. Theimplantable heart monitor 404 is vacuum sealed and impervious to bodyfluids. The electrode leads 406 and 408 connect to the heart monitor 404through a glass-to-metal feed-through, or some other acceptablefeed-through that allows the electrode leads 406 and 408 to be connectedto the internal electronics of the heart monitor 404.

The power source 424 may be a battery or other power device. In oneembodiment, the power source 424 is a lithium iodine or lithium silverchromate battery because of the extremely long battery life.Alternatively, the power source 424 may be any other solid state powerdevice based on the power requirements.

The processor 420 is a micro processing device or unit for performingcalculations, analysis, and coodinating the operation and control of theheart monitor 404. The processor 420 may include logic for controllingthe functions and monitoring capabilities of the IRAM 420. Thethermistor 416 may be a thermometer or a variety of temperaturesensitive semiconductor elements. The thermistor 416 allows the heartmonitor 404 to determine the patient's temperature which may indicatewhether there is any infection or whether symptoms are temperaturerelated.

The memory 418 is a storage device for storing digital or analog data asmeasured by the electrodes 406 and 408. The memory 418 may benonvolatile memory such as random access memory (RAM), flash memory, ora miniaturized hard drive. The A/D and peak detector 422 may be used toconvert analog data measured from the heart 410 into digital signals forstorage in the memory 418. The A/D and peak detector 422 may also beused to measure the peak amplitude of the heartbeat as recorded. Thedata may be converted from analog form to digital for ease of storage inthe memory 418 or for easier or subsequent transmission to the receiver402.

The electrode leads 406 and 408 may be attached in any number oflocations within the heart. In particular, there are three main vascularbeds in the heart 410. In some embodiments, the electrodes may beconnected in two to four locations. By monitoring the heart in multiplesites, plus a reference point in the atrium of the heart 410, themonitor 400 may perform a more sensitive evaluation of theeletrocardiographic changes in the signal amplitude and morphology orshape of the wave. The electrode leads 406 and 408 allow for a moreaccurate reading than an endomyocardial biopsy. In one example, the leftlead, electrode lead 408, may be placed via the coronary sinus.

Various amplifiers 430, and 432 are required for the electrodes 406 and408 of the heart monitor 404. Each amplifier may detect unipolarmyocardial signals from the screw-in or transvenous electrode leads 406and 408 placed in either the atrium or ventricle. The processor 420 mayswitch the amplifiers to sequentially record the signal amplitudes usingthe A/D and peak detector 422. The maximum and minimum amplitudesrecorded in any given period of time, such as every four hours, eighthours, or twenty four hours are used to obtain an average amplitudevalue. The average amplitude may also be determined for each activitylevel.

The amplifiers 426, 428, 430, 432, and 434 are used for the heartmonitor 404 and may have a band pass characteristic for the differentsignals that may be detected, monitored, recorded and stored. Forexample, an external transient event recorder (ETER) may have a bandpass filter centered at approximately 28 Hz. This band pass is sensitiveto varying cardiac rhythms as measured by the heart monitor 404. Thenarrow band pass filter reduces baseline drift as the patient moves.

If the monitor is monitoring an electrocardiogram signal (ECG), thecenter frequency may be approximately 80 Hz. This amplifier and filteris sensitive to baseline changes or drift due to motion and wouldrequire a correction algorithm be performed for the monitored signal bythe processor 420. For an IRAM monitor, the center frequency would beapproximately 200 Hz which is required to detect the signals that havebeen identified to change during heart rejection.

The piezoelectric accelerometer 436 may be a three axis piezoelectricsensor that determines both the position and activity level of thepatient at any given time. The piezoelectric accelerometer 436determines the activity level of the patient by converting the motionsof the patient into an electrical signal that may be filtered oramplified by the amplifier 434 to generate a signal that may be used bythe processor 420 to determine the activity level for storage in thememory 418. The piezoelectric accelerometer 436 may be used to initiatethe recording of data by the electrodes 406 and 408.

In another embodiment, the piezoelectric accelerometer 436 may be usedas an acoustic microphone to listen for lung sounds. For example, thepiezoelectric accelerometer 436 may be used to determine whether apatient has pulmonary edema, mitral stenosis, pulmonary congestion,pneumonia, or other lung problems. The previously described library mayalso include lung related sounds for determining whether thepiezoelectric accelerometer 436 has determined a lung issue that mayneed to be reported to the doctor.

The piezoelectric accelerometers 438 and 440 may detect acceleration inone or more directions. In one embodiment, the piezoelectricaccelerometers 438 and 440 may be unidirectional accelerometers formeasuring the motion of the different parts of the heart 410. Thepiezoelectric accelerometers 438 and 440 are positioned within theelectrode leads in order to best sense the motion of the heart 410. Thepiezoelectric accelerometers 438 and 440 may also be used to measure notonly the occurrence of a heart contraction, but the force of the heartcontractions as well.

The telemetry circuitry 414 is the circuitry used to wirelessly transmitdata to the receiver 402. The telemetry circuitry 414 may use any numberof wireless protocols to send the data to the receiver 402. Telemetryprotocols may include any number of RF signals including BLUETHOOTH®,WIFI®, a specialized medical signal, and other protocols using low powersignals. The telemetry circuitry 414 may include a transmitter and insome cases a receiver for receiving verification that the recorded datahas been received by the receiver 402. During the time that thetelemetry circuitry transmits data to the receiver 402, the processor420 may disable the amplifiers 426, 428, 430, 432, and 434 for a shortperiod of time in order to conserve power and ensure that the datatransmission does not interfere with the detection of cardiac signals.The telemetry circuitry 414 may terminate sending or retrying to senddata once a handshake or confirmation signal is received from thereceiver 402.

In another embodiment, the telemetry circuitry 414 may use radiofrequency identification (RFID). For example, the telemetry circuitry414 may only be activated when in proximity to the receiver 402. Thereceiver 402 may temporarily power and receive data from the heartmonitor 404 by transmitting a power signal similar to the use of RFIDtags.

The magnetic reed switch 412 may be used to manually activate the heartmonitor 404 to send the recorded data. The magnetic reed switch 412 maybe activated by placing an activation magnet over the monitor. Themagnetic reed switch 412 may be any variety of magnetically sensitivesemiconductor elements. For example, if the patient has experienced aheart event, the patient may use a magnet to activate the magnetic reedswitch 412 to send the recorded data from the telemetry circuitry 414 tothe receiver 402.

FIG. 5 is an alternative embodiment of a monitor system in accordancewith the illustrative embodiments of the present invention. Monitor 500includes most of the elements described in FIG. 4 with a few exceptions.In monitor 500, the electrodes 406 and 408 do not include piezoelectricaccelerometers and as a result there is no need for additionalamplifiers. For example, the monitor 500 may be an internal transientevent recorder (ITER) for recording heart events and subsequentlynotifying the doctor and/or patient through the receiver 402.

In monitor 500, the electrode lead 406 may be placed in the right atrialappendage for detecting near field P waves and far field R waves.Alternatively, the electrode lead 406 may be placed in the right atrialappendage for detecting P waves and the electrode lead 408 may be placedin the right ventricle for detecting R waves independently.

FIG. 6 is an embodiment of an external monitor system in accordance withthe illustrative embodiments of the present invention. External monitor600 may include many of the elements previously described for FIGS. 5and 6. The external monitor 600 further includes GPRS circuitry 602,button 603, and electrocardiogram electrodes 604, 606, and 608. Inaddition, the health monitor system of FIG. 6 includes patient 610, GPRSserver 612, and web interface 614. The external monitor 600 may be wornor attached to the patient 610 in any number of ways. For example, theexternal monitor 600 may be worn on the patient's belt for convenienceand easy access.

The ECG electrodes 604, 606, and 608 are attached to the patient 610 inthe traditional manner. In one embodiment, once a heart event or otherimportant data is recorded by the external monitor, the GPRS circuitry602 may automatically transmit the data to the GPRS server 612 using theGPRS protocol. The GPRS circuitry includes the software and hardwarenecessary to send and receive data using GPRS. The doctor, patient, orother user may be provided access to the web interface 614 to review themonitored heart data. The web interface 614 may require that the GPRSserver 612 be provided a password, authentication, or other securityelement for ensuring that the patient's data is only accessible byauthorized parties. In one embodiment, the GPRS server 612 mayautomatically send an alert, email, or other message to the doctor,patient, or other user indicating that the external monitor 600 hasrecorded and transmitted heart event data.

Alternatively, the patient, upon feeling a symptom believed to be heartrelated, may activate the button 603. Once asserted, the button 603sends a transmit signal to the GPRS circuitry 602 that automaticallytransmits the heart event data recorded by the external monitor andcorresponding ECG electrodes 604, 606, and 608 to the GPRS server 612indicating that this transmitted data was associated with a symptom. Thepower source 424 of the external monitor 600 may be rechargeable so thatthe patient may easily charge the external monitor 600 at night or addnew batteries as needed. For example, the patient 610 may place theexternal monitor 600 in a charging cradle at night for mobile use duringthe day, much like a cellular phone or, if separate rechargeablebatteries are used, replace the batteries in the device with fullyrecharged batteries and place the depleted batteries into the batterycharger.

FIG. 7 is an example of a screw-in myocardial electrode lead inaccordance with the illustrative embodiments of the present invention.An electrode lead 700 includes various elements including a screw-in tip702, a piezoelectric accelerometer 704, wires 706, 708, and an electrode710. The electrode lead 700 is a particular implementation of theelectrode leads 406 and 408 of FIG. 4. The heart monitor preferablyincludes two electrode leads with one of the leads placed such that bothright ventricular contractions and right ventricular depolarizationsignals may be detected. The second lead is preferably positioned suchthat both left ventricular contractions and left ventriculardepolarization signals may be detected. However, any number of leadconfigurations may be used that allow both electrical and mechanicalsignals to be effectively received for monitoring.

The screw-in tip 702 is used to connect the electrode lead 700 to themuscle of the heart. The screw-in tip 702 may be attached myocardiallyor transvenously. Transvenous leads are passed into the heart via a veinand the screw tip is deployed after venous insertion. The electrode lead700 may have an active fixation tip, such as the screw-in tip 702 or mayinclude a passive fixation tip when placed transvenously.

The piezoelectric accelerometer 704 may be used to measure movement ofthe heart or alternatively may be used to measure the force of thecontraction. The piezoelectric accelerometer 704 may be a variety ofdifferent sizes, thicknesses, shapes and metalization options.

As mentioned, the piezoelectric accelerometer 704 may be used as amicrophone using a technique of acoustic cardiology. With acousticcardiology, timing events are monitored using heart sounds, such asvalve closure, which are a second order effect of the ventriclescontracting. By using a piezoelectric sensor in the electrode lead 700,the monitor may record the primary indicator of ventricular contractionfor determining the condition, strength, and relative performance of theheart.

The piezoelectric accelerometer 704 is connected to the monitor on oneend and the electrode through the wire 706. The electrode 710 acts as areference point to the piezoelectric accelerometer 704 and makes contactwith body tissue. The voltage and current measurements recorded by thepiezoelectric accelerometer 704 are passed to the monitor through wire706. The wires 706 and 708 may be any transmission medium able toconduct signals received from the screw-in tip 702 and piezoelectricaccelerometer 704 to the body of the monitor. In one embodiment, thepiezoelectric accelerometer 704 is connected to an amplifier, such asamplifier 426 of FIG. 4 which is referenced to the titanium enclosurethat is in contact with subcutaneous body tissue. The right ventricularscrew-in lead tip 702 is connected to the amplifier 430 by the wire 706.The wire 708 passes-through the electrode 710 without making contact.For example, the electrode 710 may include an insulated pass-through bywhich the wire 708 continues without making electrically contacting theelectrode 710. Amplifier 430 of FIG. 4 is also referenced to thetitanium enclosure that is in contact with subcutaneous body tissue.

Thus, both the piezoelectric accelerometer 704 and the screw-inelectrode 702 are connected to amplifiers referenced to the patient'ssubcutaneous tissue for measurement of both the mechanical movement ofthe right ventricle and the electrical depolarization signal or IMEG. Asimilar configuration for amplifiers 428 and 432 of FIG. 4 exists forthe left ventricular electrode lead.

The use of electrode lead 700 is particularly useful for the monitorbecause of the ability to measure the contractile movement, contractileforce, and timing of the contraction. The timing measurements areparticularly useful when the two leads are attached to the left andright ventricle. The electrode lead 700 may also be used for cardiacpacing in the case where pacemaker functionality is integrated with themonitor.

FIG. 8 is a sample of heart data in accordance with the illustrativeembodiments of the present invention. Table 800 includes variouselements including an IRAM serial number 802, a patient number 804, aprotocol 806, and a date 807. Various data may be recorded by electrodelead 1 808 and electrode lead 2 810. The data for electrode leads 1 and2 808 and 810 includes a number of readings 812, IMEG amplitude 814,average IMEG average 816, IMEG amplitude 818, time 820, dV/dt 822, andaverage dV/dt 824.

Table 800 is an example and shows only two sets of monitored andrecorded heartbeats for two, five minute intervals. The recorded data oftable 800 may include any number of data sets. All or a portion of thedata may be recorded and/or subsequently transmitted to the receiver.Also, the averages of all the averages may be made so that there is onlyone value for the average IMEG amplitude 816 and the average dV/dt 824.

FIG. 9 is an illustrative graph of physical activity in accordance withthe illustrative embodiments of the present invention. Graph 900includes various sections including section 902 and section 904. Thex-axis represents physical activity level 906 and the y-axis representstime 908 throughout the day. Section 902 indicates increased physicalactivity levels as sensed by piezoelectric accelerometers in a monitor,such as monitor 104 of FIG. 1.

Section 902 indicates increased physical activity levels when thepatient is awake and performing various activities. For example, thepatient may be walking and performing the activities of the day. Section904 indicates decreased activity levels when the patient is sleeping orprofoundly resting. The assessment of various activity levels is made bymonitoring the acceleration change in the piezoelectric accelerometerper unit time or dA/dt.

The monitor may be set to monitor only and/or monitor and recordphysical activity using a looping method to record events when thepatient is awake and asleep or either awake only or asleep only. Duringthe activity levels shown in 902 the monitor is not recording samples asdescribed.

Section 904 indicates decreased activity levels when the patient issleeping or profoundly resting. Once the reduced activity levels ofsection 904 are detected, the signals from the piezoelectricaccelerometer may activate the monitor to record heart data while thepatient is sleeping and to suspend recording when activity levelsindicate the patient is awake as shown by section 902. This is extremelybeneficial when used to monitor transplant patients for rejection sinceonly monitoring of IMEG and dV/dt data during sleep is useful indetecting rejection.

FIG. 10 is an example of data recorded by a monitor in accordance withthe illustrative embodiments of the present invention. FIG. 10 includesgraph 1002, graph 1004, and graph 1006. Graphs 1002, 1004, and 1006illustrate activity data that may be collected for a patient that isexperiencing improving health. Graphs 1002, 1004, and 1006 may bedisplayed to a patient, doctor, or other specialist or user forgraphically representing the progress of the patient. The graphs 1002,1004, and 1006 may be part of a graphical user interface of a computingdevice or may be displayed independently. The person viewing the graphs1002, 1004, and 1006 may specify values, parameters, or conditions fordisplaying the data. For example, the data may be shown for each hour ofeach day or for every other day as selected by the user.

Graph 1002 includes data for activity energy. The activity may bemonitored by a piezoelectric accelerometer, such as piezoelectricaccelerometer 436 of FIG. 4. The activity data is recorded by a monitor,such as monitor 104 of FIG. 1. As shown, graph 1002 indicates that theactivity energy of the patient has been steadily increasing over timewhich may indicate that the health of the patient is improving.

Graph 1004 includes data for energy duration. Energy duration mayspecify the amount of time the monitor records the patient performingactivity above a specified threshold. For example, any recorded activitylevel that does not include sleeping may be displayed in the graph 1004.As a result, the graph 1004 may specify the amount of time a patient isawake and active for determining the energy level of the patient.

Graph 1006 includes data for combined sensor data. Graph 1006 may be acombination of data and factors. For example, graph 1006 may include thedata measurements as shown in graph 1002 and 1004. As a result, a doctormay more easily evaluate the condition of the patient based on theactivity levels performed by the patient and the amount of the time thepatient spends performing that activity.

FIG. 11 is an example of data recorded by a monitor in accordance withthe illustrative embodiments of the present invention. FIG. 11 includesgraph 1102, graph 1104, and table 1106 similar to those of FIG. 10.Graphs 1102, 1104, and table 1106 illustrate activity data that may alsobe collected for a patient that is experiencing improving health.

The graph 1102 indicates the activity duration. Graph 1102 may indicatethe amount of time the monitor records the patient active at one or moreactivity levels as measured per hour, day, week, month or year. Forexample, graph 1104 may display the amount of time the patient engagesin significant activity each day. Graph 1104 may specify the energyduration for one or more activity levels as selected by the user.

The graph 1104 is an indirect assessment of physiological status. Theindirect assessment of physiological status may include a number ofvalues or factors. The graph 1104 may include data that is scaled,averaged, or otherwise mathematically manipulated to provide a graphicalrepresentation, such as a bar chart, of the overall health of thepatient. For example, graph 1104 may include an average for all recordedactivity levels and the duration the patient is active in that activitylevel as well as a factor for sleep.

Table 1106 may include any number of data values measured by themonitor. Table 1106 may show data as recorded for each day. Table 1106may include data values for activity (reciprocal of sleep), the activitythreshold or exercise level, and the activity duration or time ofexercise. This data may be added to form a total that may be used for adoctor in measuring all activity parameters for a patient in order toobtain a more sensitive and specific evaluation of a patient's overallhealth status.

FIG. 12 is an example of data recorded by a monitor in accordance withthe illustrative embodiments of the present invention. FIG. 12 includesgraph 1202 and table 1204. Graph 1202 may indicate the target or overallhealth level of the patient. Table 1204 illustrates data that may bemeasured and recorded to generate graph 1202. Graph 1202 and table 1204suggest that the patient's health status is deteriorating.

FIG. 13 is a graphical illustration of threshold levels in accordancewith the illustrative embodiments of the present invention. The monitorpreviously described may be constantly monitoring and recording data ormay only record data that is above a specified threshold. The thresholdmay be a specified activity level as measured by the monitor,piezoelectric accelerometers, or both. Graph 1300 illustrates variousthreshold levels including threshold A 1302, threshold B 1304, thresholdC 1306, and threshold level D 1308. The thresholds level 1 1310, level 21312, level 3 1314, and level 4 1316 are represented by dotted lines asshown. The x-axis 1318 of the graph 1300 represents time and the y-axis1320 of the graph represents piezoelectric accelerometer output. Thepiezoelectric accelerometer output may be measured by one or morepiezoelectric accelerometers or a multi-axis accelerometer in the bodyof a heart monitor, such as monitor 104 of FIG. 1. The piezoelectricaccelerometer output of the y-axis 1320 may be represented by a voltagethat indicates the level of energy that the patient is imparting tohis/her motions. The monitor may record the activities of the patientthroughout the day and data corresponding to the activity level andduration of time the patient spent at that activity level.

Levels 1-4 1310, 1312, 1314, and 1316 represent the automaticallyself-adjusting settings for activity threshold. For example, when thepatient is home after surgery and spends several days in bed recoveringfrom an illness, surgery, etc., the auto-threshold level may decreaseuntil the patient begins the recovery process.

FIG. 14 is a graphical illustration of threshold levels in accordancewith the illustrative embodiments of the present invention. The Levels1-4 1310, 1312, 1314, and 1316 have been auto-adjusted based on therecent activity of the patient recovering from an illness. As a result,the graph 1400 shows automatically self-adjusting threshold levels A-D1302, 1304, 1306, and 1308 as the patient begins to improve andincreases his/her activity level.

As shown in graph 1400, the Levels 1-4 1310, 1312, 1314, and 1316 haveall automatically increased above the next threshold level. Theadjustment shown in graph 1400 illustrates the categorization ofactivity into different activity levels based on trends and patienthistory. In one embodiment, the auto-adjustment of the levels 1-4 1310,1312, 1314, and 1316 may be performed by the monitor. The space, voltageor y-axis 1320 between levels 1-4 1310, 1312, 1314, and 1316 are notnecessarily linear. Statistical analysis maybe used to auto-set thedifferent threshold levels A-D 1302, 1304, 1306, and 1308 in order tocharacterize different activity measurements into the correspondinglevels 1-4 1310, 1312, 1314, and 1316. The Levels 1-4, 1310, 1312, 1314,and 1316 may also be auto-adjusted downward if the patient suffers arecovery relapse or other setback that affects the activity levelmeasured by the monitor. For example, if the patient is recovering froman illness, the patient is less likely to spend time sleeping or restingwhen recovering is progressing as it should.

FIG. 15 is a flowchart for a process for inserting a heart monitoringdevice in accordance with the illustrative embodiments of the presentinvention. The process of FIG. 15 may be implemented for a transplantpatient or other patient that needs physiological or heart monitoring.The process of FIG. 15 may be implemented by a surgeon, cardiologist orother medical technology specialist. The process of FIG. 15 allows anintramyocardial electrogram to be taken using myocardial leads ortransvenous leads.

The process of FIG. 15 begins, after the patient is medically preppedand anesthetized, as with most surgical procedures, by attaching theleads to the patient's heart (step 1502). The electrodes or leads may bepacemaker style electrode leads or modified pacemaker style electrodeleads containing piezoelectric sensors for measuring both the electricaland mechanical activity of the heart. In one embodiment, the leads maybe myocardial screw-in leads typically used for pacemaker applicationsthat are designed to screw into the myocardial wall of the heart muchlike a corkscrew. In another embodiment, the leads may be insertedtransvenously. A transvenous lead would be passed through a vein to theright ventricle. An incision in the deltoid-pectoral groove in the upperleft or right chest area may be used to find a vein in order to insertthe transvenous lead rather than inserting the leads into the heartusing a thoracotomy or other extremely invasive and dangerous procedure.

The transvenous lead may still have a screw tip, but the screw isretracted into the body of the lead. Once the lead is passedtransvenously to the right ventricle, the back end of the lead connectormay be rotated to deploy a corkscrew tip if the lead is an activefixation design or it may be a passive fixation element whereby the leadis wedged into the trabeculae carne. The two leads may be inserted intothe right ventricle. One lead is inserted for contact to the rightventricular septum, which is the wall separating the right ventriclefrom the left ventricle. The right ventricular septum is anatomicallypart of the left ventricle and sensing of its mechanical movement may bedetectable with a piezoelectric equipped electrode lead. The other leadis inserted into the apex of the right ventricle or the right lateralwall for measuring the right ventricle.

Next, the surgeon attaches the leads to the implantable rejectionassessment monitor (IRAM). The surgeon further surgically implants theIRAM (step 1506) with the process terminating thereafter. The IRAM maybe securely implanted in a subcutaneous pocket of the abdomen or in thedeltoid-pectoral area of the shoulder. The surgical procedure may beperformed in a hospital catheterization laboratory or a specialprocedures room typically with the patient usually under localanesthetic.

FIG. 16 is a flowchart of a process for performing heart monitoringduring sleep in accordance with the illustrative embodiments of thepresent invention. The process of FIG. 16 may be performed by the IRAMor heart/physiological status monitor referred to hereinafter as themonitor after having been surgically implanted.

The process begins with the monitor determining whether the patient issleeping (step 1602). The determination of step 1602 is made in order totake readings and measurements of the heart. Ideally, the best time totake measurements for transplant rejection is during alpha sleep or thesleep before rapid eye movement (REM) sleep begins. During the first fewhours of sleep, the user is most likely to have a steady heart rate,reduced emotional stress, and other factors that make measurements takenat that time the most accurate for determining heart and physiologicalstatus.

The process of FIG. 16 continuously verifies whether the patient issleeping in order to ensure the uniformity of data. For example, if themonitor determines that the patient is not asleep in step 1602, themeasurements of any data go on hold until the patient is asleep again.This provides uniform data that may be statistically analyzed over time.As a result, measurements of the heart are performed more reliably withgreater effectiveness for a real world environment where the patient issleeping and most comfortable.

The determination that the patient is asleep may be made in any numberof ways and using a combination of information and data. In oneembodiment, the monitor and specifically piezoelectric accelerometerswithin the monitor may determine the physical position of the patient.The patient is more likely to be sleeping when positioned horizontallyor reclined. The monitor may also use the heart rate of the patient todetermine whether the patient is active or resting. For example, eventhough the patient is partially reclined in a reclining chair thepatient may be watching an action movie that has stimulated emotionalstress so that adrenaline causes his heart to pump faster than normal.Even though reclined, this is not an ideal time to take heartmeasurements. The monitor may also use previous patterns to use existingdata and historic data to determine when the patient is sleeping. In yetanother embodiment, the piezoelectric sensor within the monitor may beused to determine that the patient is sleeping by monitoring theactivity variance or dA/dt, where dA/dt is a change in activity per unittime. Little or no activity variance is a good indicator that thepatient is sleeping.

If the patient is not sleeping, step 1602 is repeated until the monitordetermines that the patient is asleep. Once the patient is determined tobe asleep in step 1602, the monitor measures the amplitude and dV/dt ofthe intramyocardial electrogram (IMEG) of the right ventricle and leftventricle for a predefined number of heartbeats at a specified timeinterval (step 1604). The measurements of the left and right ventriclefor amplitude and dV/dt may be made individually or simultaneously. Inone example, the monitor may have a predefined number of ten heartbeatsto evaluate and a specified time interval to view ten heartbeats everyfive minutes. As a result, the monitor records ten heartbeats every fiveminutes for amplitude and dV/dt for each ventricle or lead. In somepatients, the heart rate is naturally elevated because of transplant,drugs or other factors. Measurements for the predefined number ofheartbeats may be measured much faster because of their naturally fasterheart rate.

The monitor averages the peak amplitude and dV/dt of the IMEG for eachmeasurement to calculate a measurement average of amplitude and dV/dt(step 1606). By taking a running average, the monitor is able toaccurately monitor heart statistics while minimizing the values thatmust be stored in memory. As a result, the monitor may take a very largesample size each night or each time the patient sleeps for providing thepatient's doctor important information regarding heart and physiologicalstatus.

The monitor determines whether the measurement threshold is met (step1608). The measurement threshold is a specified number of measurementsor samples. The measurement threshold may be set by default or may becommunicated to the monitor by the patient's doctor based oncircumstances and need. For example, the measurement threshold may bethirty six samples for each ventricle and based on twelve measurementsper hour for three hours.

If the measurement threshold is not met, the monitor determines whetherthe patient is sleeping (step 1602). If the monitor determines themeasurement threshold is met in step 1608, the monitor averages therespective measurement averages for all measurement intervals tocalculate an overall measurement average for both ventricles (step1612). The overall average is a single number for amplitude and dV/dtfor each ventricle. In another embodiment, the overall average of step1612 may be a single number for the entire heart for amplitude anddV/dt.

Next, the monitor transmits the overall average for amplitude and dV/dtfor each ventricle and a representative sample rhythm IMEG orelectrocardiogram (ECG) strip to a receiver (step 1614) with the processterminating thereafter. The data may be transmitted in a number ofdifferent ways. In one embodiment, the data may be transmitted at apredetermined time, such as 7:00 a.m. every morning. In anotherembodiment, the overall averages may be transmitted to the receiver atany time the monitor detects the presence of the receiver fortransmission. In yet another embodiment, the overall averages may betransmitted to the receiver when the patient awakes from sleep evidencedby an increase in the monitored activity variance, dA/dt. The receivermay be a unit that is connected to a communications line, such as anInternet connection or a modem for sending data to a data processingsystem, server, or other computing platform for access by the doctor. Inanother embodiment, the patient may wear the receiver on a belt orharness and may use wireless technology, such as general packet radioservice (GPRS) to transmit the data to a data processing system, server,or other computing platform for access by the doctor. The receiver mayalso be a specially programmed cellular phone designated to send andreceive data from the monitor.

The representative sample is one entire sample measurement that isrecorded by the monitor. The representative sample illustrates theentire heartbeat wave form for analysis and understanding of thecondition of the patient's heart. For example, the representative samplemay show a ten beat pattern for both the left and right ventricle. Therepresentative sample transmitted during step 1614 allows a doctor orother specialist to see what is happening with the heart in order toperform other analysis or determinations. The representative sample alsoindicates the quality of the signal being received by the monitorensuring that the monitor is working properly and that the electrodesare still properly connected.

The monitor may also be configured to continuously watch for a heartevent, such as arrhythmm, trigeminy, bradycardia, tachycardia, andpremature ventricular contractions (PVC). When an event is detected, themonitor may immediately transmit the information to the receiver fortransmission and subsequent analysis by the doctor. The monitor may alsotransmit based on a predefined time period or other preferences.

FIG. 17 is a flowchart of a process for measuring activity levels inaccordance with the illustrative embodiments of the present invention.The process of FIG. 17 may be implemented by a heart monitor orphysiological status monitor. The process of FIG. 17 begins by startinga timer (step 1702). The timer ensures that the monitor transmitsinformation or a status report once a day regardless of the sleepingactivity of the patient.

The monitor then determines an activity threshold (step 1704). Theactivity threshold may be determined using various information andfactors. The activity threshold may indicate the current activity levelof the patient. The activity level indicates the amount of energydetected by the piezoelectric sensors in the monitor imparted by thepatient's movements. In one embodiment, the activity level is determinedby piezoelectric accelerometer within the monitor that specify the levelof movements being performed. The thresholds are based on the output ofthe accelerometer which may be a voltage, other digital signal, oranalog signal. There may be any number of activity thresholds, tiers, orranges that indicate a specified activity level.

In one embodiment, there are four thresholds, any activity less than thefirst threshold indicates that the patient is asleep. Activity above thefirst threshold, but below the second threshold, indicates the patientis performing moderate movement. Activity above the second threshold,but below the third threshold, indicates that the patient is performingsignificant movement. Activity above the third threshold, but below thefourth threshold, indicates that the patient is performing vigorousmovement. All activity for the patient throughout the day may becategorized into one of the threshold levels. The activity thresholdsspecify a categorization for each activity level. In another example,the activity level may be determined based on the heart rate of thepatient and the activity as determined by the piezoelectricaccelerometer.

The monitor determines whether to adjust the activity thresholds (step1706). The determination to adjust the activity threshold may be made onpast data trends or based on new activity levels. For example, if thepatient has recently been performing vigorous movement, the thresholdlevel may be higher than if the patient was relatively sedentary. Somepatients may never reach the point of performing vigorous movement. As aresult, the threshold levels are automatically set and modified based onthe measured activity of the patient. The determination of step 1706 maybe made by a processor, logic, memory, and piezoelectric sensors withinthe monitor. The initial threshold ranges or values may be setarbitrarily or based on values determined for previous patients withsimilar circumstances.

If the monitor determines to adjust the activity threshold, then themonitor adjusts the activity thresholds based on the activity level(step 1708). Different patients may have different threshold levels. Forexample, many patients are naturally very active and may have higherthreshold levels whereas other users are by nature much more sedentaryor inactive. In another example, the active patient may get very sick orundergo a transplant necessitating an adjustment of the activitythresholds as the patient recovers and slowly returns to a more activelifestyle. The activity threshold is auto-set by the monitor based onactual patient activity measured by the monitor as objectively measuredby one or more piezoelectric accelerometers. Next, the monitordetermines the activity threshold (step 1704).

If the monitor determines not to adjust the activity threshold in step1706, then the monitor determines whether the threshold level is one orbelow or two or above (step 1710). If the threshold is at one, themonitor measures and stores the sleep time and temperature (step 1712).

If the monitor determines the threshold is two or above, the monitormeasures and stores a recording of time awake, activity amplitude,activity duration, and temperature (step 1714). By measuring and storingactivity level measurements it is easy to see whether a patient isimproving, getting worse, or stable with regard to physical activity. Asa result, a doctor may objectively categorize a person's health based onactivity. The data stored by the monitor is particularly suitable forgraphing activity levels over time. The time awake indicates whether thepatient is sleeping enough and active during the day. The activityamplitude and duration indicate what activity level is being reached andfor how long.

After steps 1712 and 1714, the monitor determines whether to transmitdata (step 1716). In one embodiment, the monitor may not transmit thedata until the timer has reached a specified value or range. Thedetermination may be made based on availability of the receiver, amountof stored information, or other factors. If the monitor determines notto transmit data in step 1716, the monitor determines the activitythreshold (step 1704).

If the monitor determines to transmit data in step 1716, the monitortransmits measurements to a receiver (step 1718). The receiver may be ahardwired unit that is connected to a communication line. Alternatively,the receiver may be worn by the patient and may use wireless technologyto broadcast the recorded data to a specified device, interface, portal,server, or recipient. Next, the monitor determines whether there is ahandshake (step 1720). The handshake indicates whether the informationwas properly received. For example, the handshake may be received from atransceiver if the data transmitted from the monitor is received withouterrors. The handshake may be a confirmation or other signal indicatingthe data has been successfully received. If there is not a handshake,the monitor waits for a period of time (step 1720) and determineswhether to transmit the data (step 1716).

If the monitor determines there is handshake in step 1720, the monitorclears the memory and resets the timer (step 1724). The memory iscleared to make space for new data. The reset timer indicates that datahas been transmitted for that day or other specified time period and isreset to begin again. The monitor starts the timer (step 1702). Theprocess of FIG. 17 is repeated continuously to monitor the status of thepatient. As a result, doctors or other medical personnel may use thedata measured and stored in steps 1712 and 1714 to determine the type ofactivity the patient is engaging in and how often the activity level isperformed. The doctor may use previously recorded data to view changesin the patient's activity that are a direct byproduct of health andwell-being. For example, during a patient/doctor visit, the doctor maysay “let's pull up your data from last month and see how you are doing.”The doctor may recommend new activities, drugs, or perform additionalanalysis based on information from the patient and the recorded data.For example, the patient may imply that he has been exercising, but themonitor may give a more realistic or accurate report of activity levels.The recorded data transmitted to the doctor provides an indirectmeasurement of cardiac performance, neurological, and physiologicalperformance. The monitor is useful for patients that experienceinactvity, over activity, or other combinations of activity problems.

FIG. 18 is a flowchart of a process for detecting heart events inaccordance with the illustrative embodiments of the present invention.The process of FIG. 18 may be implemented by a heart monitor orphysiological status monitor. The process begins with the monitordetermining whether a heart event is detected (step 1802). The heartevent may be bigeminy, trigeminy, bradycardias (slow heart rates),tachycardias (fast heart rates), premature ventricular contractions(PVC), multiple PVCs, any kind of arrhythmia or other heartbeatabnormality. The heart event may be detected in step 1802 by monitorlogic. For example, the monitor logic may compare the patient's normalheartbeat morphology (wave shape) that has been previously recorded andstored, in either analog or digital format, with the current heartbeatto determine if there is an irregularity. If a heart event is notdetected, the monitor continues to repeat step 1802 until a heart eventoccurs.

If a heart event is detected in step 1802, the monitor records andstores the heart event in event data (step 1804). In one embodiment, themonitor is continuously recording waveforms recorded received from theelectrode leads. However, once an event is detected in step 1802, aspecified time period before, during, and after the heart event may berecorded. For example, the monitor may store the heart event data aswell as thirty seconds before and after the event. The pre-event timeframe and post event time frame may be set by default or may beprogrammed based on the needs and condition of the patient. The sampleor recorded data may be stored in analog or digital form. For example,the monitor may use analog to digital converters to convert therepresentative heartbeats or waveforms into digital data.

Next, the monitor compares the heart event with a database (step 1806).The database may be a program or memory that stores a library of heartevents for comparison. The database may be a portion of the memory thatspecifies the signature, characteristics or parameter of each possibletype of heart event. In one embodiment, if the patient has alreadyexperienced a confirmed heart event the current event may be comparedwith the stored event. The recorded heart event may be recorded indigital or analog form based on accuracy of comparison. The database mayinclude a library of heart events that may be compared against the heartevent detected in step 1802. In one embodiment, the monitor logic mayspecify the severity of the event, if known, for reference by a doctor.

The monitor determines whether the heart event is known (step 1808). Ifthe heart event is known, the monitor inserts a heart eventcategorization in the event data (step 1810). For example, the monitormay insert a header or label that specifies that the recorded heartevent is a tachycardia PVC. The data inserted in step 1810, may beuseful to a doctor or other medical specialist that may respond to thepatient's heart event.

After step 1808 or 1810, the monitor determines whether transmission ispossible (step 1812). The monitor may include transmission logic forspecifying when and how data is sent from the monitor. In oneembodiment, a detected heart event is to be sent immediately oncereceived. As a result, the monitor may need to determine in step 1812,whether a mobile receiver or other transceiver is available. Forexample, the monitor may detect a status or availability signal when inproximity to a receiving device that indicates that the monitor maytransmit the event data. In another embodiment, the transmission logicmay specify that heart events are only to be sent at a specified timeperiod. Alternatively, the patient may wear a portable receiver that isused to send the event data using GPRS as soon as received.

If the monitor determines transmission is possible, the monitortransmits the event data to a receiver (step 1814) with the processterminating thereafter. As previously discussed, the event data may besent to a receiver that retransmits the event data to the doctor. Theevent data may also be sent directly to the doctor, to a web interface,a server, or other receiving device. As part of step 1814, the monitormay require that a handshake or data receipt confirmation is received.For example, as part of step 1814 once a receipt handshake has beenreceived from the receiver or transceiver, the monitor may delete theevent data to make space available for other heart events and otherrecorded data.

If the monitor determines transmission is not possible in step 1812, themonitor waits for a time period (step 1816) and then again determineswhether transmission is possible (step 1812). The event data ismaintained until it may be transmitted to a receiver in step 1814. Insome cases, the monitor may record multiple heart events before the datamay be transmitted because transmission is not possible.

FIGS. 19-23 illustrate examples of pages that may be displayed in agraphical user interface accessible by the patient, doctor or otherauthorized individual. The graphical user interface may be displayed tothe user through the Internet using a web browser, program application,or database executed one more computing devices, such as a personalcomputer or PDA. The examples shown include pages and fields fordoctor's demographics, patient listing, new patient enrollment, setparameters, billing, heart data, activity and event data, and samples ofrecorded events.

FIG. 19 is an example page for demographics in a graphical userinterface in accordance with the illustrative embodiments of the presentinvention. Page 1900 includes various information, sections, or detailsthat may be used to identify the doctor or other user accessing the page1900 of the graphical user interface. The page 1900 may include section1902, section 1904, section 1906, and section 1908.

Section 1902 may include data for identifying the physician which mayinclude a practice name, one or more physician names, and a UniquePhysician Identification Number (UPIN) number of each physician.

Section 1904 may specify the address of each doctor including address,telephone number, and other contact information. This may allow thedoctor to be contacted in the event a heart event is detected or onephysician needs to contact another. Section 1906 may includeauthorization information for accessing the graphical user interface,page 1900, and other patient information. Section 1908 may includespecial instructions regarding the doctor or other notices that may behelpful.

FIG. 20 is an example page for patient listing in a graphical userinterface in accordance with the illustrative embodiments of the presentinvention. Page 2000 may include data for any number of patients. Page2000 may be particularly useful for tracking numerous patients that areusing a monitor. Section 2000 may include various information regardingpatients which may include a patient name and number assignment,address, phone, device model and serial number for the monitor, andinformation for setting parameters. The patient number and device modeland serial number may be part of the data that is sent and received fromthe monitor in order to ensure that the recorded data is properly routedto individuals authorized to see the patient's data.

FIG. 21 is an example page for a new patient enrollment in a graphicaluser interface in accordance with the illustrative embodiments of thepresent invention. Page 2100 may be used to enroll a new patient. Forexample, a patient that has recently had a heart monitor surgicallyimplanted may have his/her patient information entered into page 2100.The information may specify the patient's name, address, contactinformation, device model, serial number, and patient number, areferring physician, and next of kin. All or a portion of thisinformation may be stored in the memory or storage of the device fortransmission from the monitor or receiver. Alternatively, a serialnumber embedded in the data sent from the monitor may be used to linkthe data with the patient.

FIG. 22 is an example page for setting parameters in a graphical userinterface in accordance with the illustrative embodiments of the presentinvention. Page 2200 may allow a user to set parameters for themonitoring device or for reviewing the data received. The page 2200 mayinclude the patient information which may specify name, address, contactinformation, physician, and device information. Page 2200 may alsospecify monitoring criteria for the monitor.

Monitor criteria may specify parameters that are to be monitored by theheart and important thresholds that may be significant. Monitor criteriamay also specify the monitoring of certain heart events, heart rate, andwave form details. In one example, the monitor may monitor the timeintervals, slope, amplitude, and rise time between the PR, QRS, QT, andQS points of the heartbeat waveform. The monitoring criteria may furtherspecify what events are important and what conditions may be ignored.

FIG. 23 is an example page for a recorded event in a graphical userinterface in accordance with illustrative embodiments of the presentinvention. Page 2300 may be displayed to a user when a heart event orother data has been received. Page 2300 may include a sample, portion orthe entire event as recorded by the heart monitor. Page 2300 may specifypatient information, the event date, and the type of monitor. The page2300 may specify the symptoms, measurements, and other findings. Forexample, the patient may be experiencing an irregular heartbeat. Themonitor detects that the patient's heartbeat is irregular and recordsthe data for immediate or subsequent transmission to the receiver. Thereceiver may transmit the data to a server or directly to the doctor forreview. The doctor may use the data to immediately ascertain theseriousness of the situation in order to provide the patient advice orimplement additional medical procedures and medication for the good ofthe patient.

The previous detailed description is of a small number of embodimentsfor implementing the invention and is not intended to be limiting inscope. The following claims set forth a number of the embodiments of theinvention disclosed with greater particularity.

1.-15. (canceled)
 16. A method for determining activity levels of apatient, said method comprising: determining an activity level based onactivity of the patient, the activity is measured by one or more piezoaccelerometers in a surgically implanted monitor; measuring and storingdata regarding awake time, activity amplitude, activity duration andtemperature; and transmitting the data to a receiver.
 17. The methodaccording to claim 16, further comprising: dynamically adjusting aplurality of activity thresholds that establish a plurality of activitylevels.
 18. The method according to claim 16, wherein the measuring andstoring data is performed for each of the plurality of activity levels.19. The method according to claim 16, further comprising: calculating aphysiological status value by adding values of the data for indirectlydetermining health of the patient.
 20. A heart monitor, comprising: oneor more electrodes for sensing electrical signals from a heart atdifferent locations in the heart, the one or more electrodes includingpiezoelectric accelerometers for measuring motion of the differentlocations; one or more amplifiers operatively connected to the one ormore electrodes configured to filter the electrical signals receivedfrom the one or more electrodes; a monitor piezoelectric accelerometerfor measuring activity levels of a patient; a processor operativelyconnected to the amplifiers configured to control the electrical signalssensed by the one or more electrodes; a storage operatively connected tothe processor configured to store data associated with the electricalsignals and activity levels; and telemetry circuitry operativelyconnected to the processor configured to wirelessly send the data to areceiver.
 21. The heart monitor according to claim 20, wherein theelectrical signals are atrial unipolar intracardiac depolarizationsignals (P waves) and unipolar ventricular intracardiac depolarizationsignals (R waves).
 22. The heart monitor according to claim 20, whereinthe piezoelectric accelerometers for electromechanical measuring theperformance of the heart.
 23. The heart monitor according to claim 20,wherein the heart monitor is surgically implanted, wherein the one ormore electrodes are intramyocardial electrodes.
 24. The heart monitoraccording to claim 20, wherein the electrical signals are a heartbeatwaveform and include a change in voltage per time (dV/dt) and anamplitude.
 25. The heart monitor according to claim 20, wherein thepiezoelectric accelerometers measure the activation time and contracttime of ventricles of the heart.
 26. The heart monitor according toclaim 20, further comprising: a magnetic reed switch configured to allowthe patient to manually activate the telemetry circuitry for immediatelytransmitting the data to the receiver.
 27. The heart monitor accordingto claim 20, further comprising: a thermistor for recording bodytemperature.
 28. The heart monitor according to claim 20, wherein thetelemetry circuitry includes general packet radio service (GPRS) fortransmitting data to a web server wherein the web server is available tousers authorized to view the data of the patient.
 29. The heart monitoraccording to claim 22, wherein the storage includes a library fordetermining whether heart data and lung data acoustically recorded bythe piezoelectric accelerometers and monitor piezoelectricaccelerometers indicates that a heart event is occurring.
 30. The heartmonitor according to claim 20, wherein the heart monitor is any of animplantable rejection assessment monitor, external transient eventrecorder, internal transient event recorder, implantable heart monitor,and pacemaker.